Conventionally, various table calculations are performed with a computer by using table calculation software. The table structure employed for conventional table calculation software is a matrix structure comprising rectangular cells arranged in rows having the same number of cells and columns having the same number of cells. For example, with the row order being represented by numerals and the column order by letters, as is shown in FIG. 17, a 6.times.4 matrix structure having rows 1 through 6 and columns A through D is employed, with a variety of data for use in calculations, and results obtained through calculations entered in the elements in the matrix.
The individual elements of the matrix correspond to the rectangular cells, and in FIG. 17, 10, a datum item, is entered in rectangular cell B2 in the second row and the second column. When the data in the cells in the second row is added together and the sum is displayed in cell D2 in the second row and the fourth column, 35, the result, is entered in cell D2 by defining an expression, for example, SUM (A2:C2), for cell D2.
Furthermore, rows or columns can be added to or deleted from the prepared table. When, for example, one column is inserted between column A and column B, column B and the following columns are shifted in order, and when the data in the first through the fourth column are added together, the sum is displayed in the fifth column.
According to conventional table calculation software, data is stored in a matrix structure of n rows and m columns; therefore, it is premised that the cells are prepared in the same number for the rows and in the same manner for the columns, and according to the table calculation software, a table such as is shown in FIG. 18 can not be prepared for table calculation. The table in FIG. 18 and the table in FIG. 17 differ in that the table in FIG. 18 does not have the matrix structure of n rows and m columns that is used by the conventional table calculation software, but has a table structure wherein irregularly divided cells holding different numbers are provided for each row and each column. Another difference between the tables in FIGS. 17 and 18 is that in FIG. 18 a cell is divided into two areas by a diagonal ruled line and data is entered in the two separate areas.
There are many demands by users who employ table calculation software for table calculations to be performed using a table such as is shown in FIG. 18. The demand has recently increased, especially in Japan and other countries where Chinese characters are used and where tables are frequently employed in which chinese characters, etc., are displayed vertically and horizontally.
Data storage and table calculation when the table in FIG. 18 is used should be as follows; for example: charges for "gas" and "electricity" in "April" are entered in their respective cells and the sum of these entries is put into a large cell that is adjacent to the "gas" and "electricity" cells. The sum is added to fee data, which is entered in an "others" cell, and the result is entered in a "sub-total" block. Then, the "sub-totals" for the individual months are added together, with the sub-total for the current month being entered in the area above the diagonal ruled line and the "Grand Total" to date being entered in the lower area, as is shown in the lowermost blocks for "May" and "June".
Although tables such as the one in FIG. 18 are frequently used, conventional table calculation software can not cope with a table having an irregular structure (such as is shown in FIG. 18) when table calculations are performed. Currently, therefore, in order to prepare such a table and display or print it, an operator must first draw a frame with ruled lines for a table by using a word processor, perform the necessary calculations employing a manual calculator or an auxiliary calculator, such as an electronic calculator, and then enter the calculation results in predetermined locations in the prepared table.
During the process of overcoming the above shortcoming, the present inventor searched background concerning table calculation for a table such as that shown in FIG. 18 and found the following reference documents. The table structure system disclosed in Japanese Unexamined Patent Publication No. Hei 2-148170, does not adopt a table structure having a regular shape wherein each row has the same number of cells and each column has the same number of cells, but instead employs a table structure having an irregular shape wherein each row has a different number of cells and each column has a different number of cells. According to the disclosed technique, a table structure having a regular shape wherein each row has the same number of cells and each column has the same number of cells is assumed by providing imaginary lines in a table having an irregular shape, and after frame presence/absence information and frame linking information are entered, table structuring data is prepared by using the same method as for a table structure having a regular shape. In Japanese Unexamined Patent Publication No. Hei 2-148170, it is premised that a table having an irregular shape printed in advance is read by a scanner, etc., and table structuring data, for defining a table structure, is created from ruled line data that forms a table that has been read and is on hand. This technique does not employ a display device, such as that of a computer, to prepare a table and perform table calculations. Therefore, the editing of a prepared table, such as performing addition and the deletion of rows and columns, the inputting of specific data, and the table calculation method are not disclosed at all.
In Japanese Unexamined Patent Publication No. Hei 5-20340 it is disclosed that diagonal ruled lines are drawn in cells in a spread sheet. A method intended merely for displaying diagonal ruled lines is described, and there is no reference to a calculation method using a table that has diagonal ruled lines.
As is described above, although there is strong demand from users for the preparation of a table, such as the one shown in FIG. 18, that is easy to see and to understand, and for table calculation to be facilitated, current, conventional techniques do not provide satisfactory means to satisfy this demand.
It is therefore one object of the present invention to provide a table structure with which a table can be prepared that is easy to see and understand and with calculations that can be easily performed, i.e., with which the degree of freedom for the designing of a table can be increased and table calculations can be easily performed.